For those who watched Apple get left for dead in the late 1990s, when Microsoft ruled the world, this was an astonishing and historical moment.

And now Microsoft has to deal with another humiliation, as another company that it had once vanquished—IBM—has also now come roaring back and surpassed it in market value.

As Bloomberg Radio observed this morning, at the close of trading yesterday, IBM was worth more than Microsoft: $214 billion vs $213 billion.

What's going on here?

MICROSOFT: Dead in the water.

Well, as the following charts show, Microsoft's stock is still 50% off the peak it hit in the tech bubble and has been dead in the water for a decade. IBM, meanwhile, has reinvented itself over the past couple of decades as a global enterprise tech services business, and its stock value has been steadily rising.

More specifically, Microsoft's once-dominant Windows and Office monopoly is under relentless attack, as the Internet reduces PC operating systems from the standard platform upon which all personal computing was based to little more than specialized device-drivers in a world with many devices. The value in personal computing has moved to mobile and the cloud, and this has allowed Apple, Google, Amazon, and other companies to barge in on Microsoft's party, eroding its power and dominance.

IBM: Resurgent.IBM, meanwhile, long ago abandoned efforts to try to win in both the enterprise and consumer markets, and instead focused all its attention on the enterprise. This market has remained healthy and tech-agnostic, and IBM's services business has continued to grow.

Eventually, Microsoft will likely be forced to make a similar choice: Focus on defending and expanding its position in the enterprise—which, despite the amount of attention its consumer offerings get, still drives the vast majority of its profits. Or watch as the rest of its monopoly is eroded away.